Currently, with development of communications technologies, to adapt to the progress of communications standards, for each network device in an existing wireless communications network such as a mobility management entity (MME), a serving gateway (SGW), a public data network gateway (PGW), or an evolved NodeB (eNB), an increasing quantity of functions are integrated in the device.
However, multiple functions of each device are closely coupled and mutually restricted, and when system performance is insufficient, free extension cannot be performed.